Bed Bath & Beyond Inc., Dillard’s Inc., Dunkin Brands and Gap Inc. and other chains have joined Merchant Customer Exchange, a mobile-payment system company formed in August by some of the largest U.S. retail chains and gasoline retailers.

Irving-based MCX members include Wal-Mart Stores Inc., Target Corp. and Dallas-based 7-Eleven Inc. and Alon Brands. The companies represent more than $1 trillion a year in annual sales retail and gasoline sales.

The group wants to create a new mobile-payment system to compete with Google Wallet and Dallas-based AT&T Inc.